Field of the Invention The present invention relates generally to integrated circuit semiconductor chips. More particularly, the present invention pertains to leadframes for bonding with the integrated circuits.
Integrated circuit manufacturers face many design challenges, including reducing the amount of noise in the integrated circuit. Resistance, capacitance and inductance, parasitics of an integrated circuit package, can result in increased signal delays and signal distortions in the electrical signals transmitted to and from the integrated circuit.
Two sources of noise in an integrated circuit package are switching noise and cross-coupling noise, or cross-talk. Switching noise may be an inductive voltage spike that occurs on a conductive path as the result of rapid current switching in the conductive path. Cross-talk is the undesirable appearance of an electrical current in a conductive path as a result of mutual capacitance and inductance between the conductive path and other nearby conductive paths. At higher frequencies, the integrated circuit is even more susceptible to noise.
One approach to reduce noise in an integrated circuit is to increase spacing between transmission lines, such as leads of a leadframe 100 as shown in FIG. 1. The individual leads 110 forming a right angle are curved in a small portion of the lead and have tightly radiused corners 118. However, as integrated circuits and electronic equipment become smaller and more complex, spacing transmission lines farther apart becomes increasingly difficult, if not impossible.
Another approach to reduce noise is to reduce the length of the transmission line on a leadframe by using diagonal leads. While diagonal leads minimize the length of the leads, the spacing between the leads would also be decreased. The decreased spacing would increase the overall cross-talk between the leads, and would therefore be undesirable.
Accordingly, there is a need for an integrated circuit package in which the above benefits are achieved and the above problems are overcome.